fans not turning on

[coldkilla]

ive got a 160 thermostat and my pcmforless chip telling the pcm to turn the fans on at 160 but all of a sudden yesterday the temp started creeping up and over 220 because the fans werent coming on. i manually engaged the contact on the relay and even jumped it out and boths times the fans came on. so i bought a new relay and sure enough, the fans still are not coming on unless i jump out the relay. wtf? if the relay is good, and the fans are good, as proved by the fact that they do come on when bypassing the relay, then why are they not coming on themselves? also, no trouble codes.

[camaro2you]

fan sensor in the block???

[coldkilla]

hhmm... im not sure of what exactly tells the fans to turn on. i know there are two coolant temp sensors on my car, one in the block and one in the water pump area, tho i cant recall at the moment which one does what. i know i replaced the one by the water pump about 2 years ago. does anyone know which does what?

[coldkilla]

did some research and it seems that the one i replaced awhile back is now bad. the waterpump sensor goes to the computer while the block sensor goes to the gauge. if the waterpump sensor fails it fails open, in a position that tells the pcm that the coolant is always cold. that will explain my fans coming on. well looks like i might have solved this. thanks for pointing me in the right direction camaro2you

[camaro2you]

shure np man.

[gotay]

I used to have tha same problem in my 1991 camaro z28 tpi a year ago.
I put the fan switch to the water pump.
The fan switch is located at the motor head on the passenger side, dont be confused w/the EST sensor.
ESC=Electronic Spark Control

[r0nin89]

Fan switch ftw :D